Hi Jax,
Unfortunately I'm no longer on Renpy 8.3.7 (the newest version seems to be 8.4), so I wasn't able to reproduce the issue
But I looked through the script anyway, and it isn't using im.Scale anywhere, so I'm not sure how the error could be happening
Can you either paste the lint error (which should show the line of the error), or try upgrading to Renpy 8.4 to see if that fixes the issue?